package edu.unc.its.tl.bb.client;

/*
 * @(#)ExtensionFileFilter.java	1.9 99/04/23
 *
 * Copyright (c) 1998, 1999 by Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */


import java.io.File;

import java.util.Hashtable;
import java.util.Enumeration;

import javax.swing.filechooser.*;

/**
 * A convenience implementation of FileFilter that filters out
 * all files except for those type extensions that it knows about.
 *
 * Extensions are of the type ".foo", which is typically found on
 * Windows and Unix boxes, but not on Macinthosh. Case is ignored.
 *
 * Example - create a new filter that filerts out all files
 * but gif and jpg image files:
 *
 *     JFileChooser chooser = new JFileChooser();
 *     ExtensionFileFilter filter = new ExtensionFileFilter(
 *                   new String{"gif", "jpg"}, "JPEG & GIF Images")
 *     chooser.addChoosableFileFilter(filter);
 *     chooser.showOpenDialog(this);
 *
 * @version 1.9 04/23/99
 * @author Jeff Dinkins
 */
public final class ExtensionFileFilter extends FileFilter {

   private static String TYPE_UNKNOWN = "Type Unknown";
   private static String HIDDEN_FILE = "Hidden File";

   private Hashtable filters = null;
   private String description = null;
   private String fullDescription = null;
   private boolean useExtensionsInDescription = true;

   /**
     * Creates a file filter. If no filters are added, then all
     * files are accepted.
     *
     * @see #addExtension
     */
   public ExtensionFileFilter() {
      this.filters = new Hashtable();
   }

   /**
     * Creates a file filter that accepts files with the given extension.
     * Example: new ExtensionFileFilter("jpg");
     *
     * @see #addExtension
     */
   public ExtensionFileFilter(String extension) {
      this(extension, null);
   }

   /**
     * Creates a file filter that accepts the given file type.
     * Example: new ExtensionFileFilter("jpg", "JPEG Image Images");
     *
     * Note that the "." before the extension is not needed. If
     * provided, it will be ignored.
     *
     * @see #addExtension
     */
   public ExtensionFileFilter(String extension, String description) {
      this();
      if (extension != null)
         addExtension(extension);
      if (description != null)
         setDescription(description);
   }

   /**
     * Creates a file filter from the given string array.
     * Example: new ExtensionFileFilter(String {"gif", "jpg"});
     *
     * Note that the "." before the extension is not needed adn
     * will be ignored.
     *
     * @see #addExtension
     */
   public ExtensionFileFilter(String[] filters) {
      this(filters, null);
   }

   /**
     * Creates a file filter from the given string array and description.
     * Example: new ExtensionFileFilter(String {"gif", "jpg"}, "Gif and JPG Images");
     *
     * Note that the "." before the extension is not needed and will be ignored.
     *
     * @see #addExtension
     */
   public ExtensionFileFilter(String[] filters, String description) {
      this();
      for (int i = 0; i < filters.length; i++) {
         // add filters one by one
         addExtension(filters[i]);
      }
      if (description != null)
         setDescription(description);
   }

   /**
     * Return true if this file should be shown in the directory pane,
     * false if it shouldn't.
     *
     * Files that begin with "." are ignored.
     *
     * @see #getExtension
     * @see FileFilter#accepts
     */
   public boolean accept(File f) {
      if (f != null) {
         if (f.isDirectory()) {
            return true;
         }
         String extension = getExtension(f);
         if (extension != null && filters.get(getExtension(f)) != null) {
            return true;
         }
         ;
      }
      return false;
   }

   /**
     * Return the extension portion of the file's name .
     *
     * @see #getExtension
     * @see FileFilter#accept
     */
   public String getExtension(File f) {
      if (f != null) {
         String filename = f.getName();
         int i = filename.lastIndexOf('.');
         if (i > 0 && i < filename.length() - 1) {
            return filename.substring(i + 1).toLowerCase();
         }
         ;
      }
      return null;
   }

   /**
     * Adds a filetype "dot" extension to filter against.
     *
     * For example: the following code will create a filter that filters
     * out all files except those that end in ".jpg" and ".tif":
     *
     *   ExtensionFileFilter filter = new ExtensionFileFilter();
     *   filter.addExtension("jpg");
     *   filter.addExtension("tif");
     *
     * Note that the "." before the extension is not needed and will be ignored.
     */
   public void addExtension(String extension) {
      if (filters == null) {
         filters = new Hashtable(5);
      }
      filters.put(extension.toLowerCase(), this);
      fullDescription = null;
   }


   /**
     * Returns the human readable description of this filter. For
     * example: "JPEG and GIF Image Files (*.jpg, *.gif)"
     *
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     * @see FileFilter#getDescription
     */
   public String getDescription() {
      if (fullDescription == null) {
         if (description == null || isExtensionListInDescription()) {
            fullDescription = description == null ? "(" : description + " (";
            // build the description from the extension list
            Enumeration extensions = filters.keys();
            if (extensions != null) {
               fullDescription += "." + (String)extensions.nextElement();
               while (extensions.hasMoreElements()) {
                  fullDescription += ", " + (String)extensions.nextElement();
               }
            }
            fullDescription += ")";
         } else {
            fullDescription = description;
         }
      }
      return fullDescription;
   }

   /**
     * Sets the human readable description of this filter. For
     * example: filter.setDescription("Gif and JPG Images");
     *
     * @see setDescription
     * @see setExtensionListInDescription
     * @see isExtensionListInDescription
     */
   public void setDescription(String description) {
      this.description = description;
      fullDescription = null;
   }

   /**
     * Determines whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description.
     *
     * Only relevent if a description was provided in the constructor
     * or using setDescription();
     *
     * @see getDescription
     * @see setDescription
     * @see isExtensionListInDescription
     */
   public void setExtensionListInDescription(boolean b) {
      useExtensionsInDescription = b;
      fullDescription = null;
   }

   /**
     * Returns whether the extension list (.jpg, .gif, etc) should
     * show up in the human readable description.
     *
     * Only relevent if a description was provided in the constructor
     * or using setDescription();
     *
     * @see getDescription
     * @see setDescription
     * @see setExtensionListInDescription
     */
   public boolean isExtensionListInDescription() {
      return useExtensionsInDescription;
   }
}
